Gas separation is important in many industries and can typically be accomplished by flowing a mixture of gases over an adsorbent that preferentially adsorbs a more readily adsorbed component relative to a less readily adsorbed component of the mixture. One of the more important types of gas separation technology is swing adsorption, such as pressure swing adsorption (PSA). PSA processes rely on the fact that under pressure gases tend to be adsorbed within the pore structure of the microporous adsorbent materials or within the free volume of a polymeric material. The higher the pressure, the greater the amount of targeted gas component will be adsorbed. When the pressure is reduced, the adsorbed targeted component is released, or desorbed. PSA processes can be used to separate gases of a gas mixture because different gases tend to fill the micropore or free volume of the adsorbent to different extents.
Another important gas separation technique is temperature swing adsorption (TSA). TSA processes also rely on the fact that under pressure gases tend to be adsorbed within the pore structure of the microporous adsorbent materials or within the free volume of a polymeric material. When the temperature of the adsorbent is increased, the adsorbed gas is released, or desorbed. By cyclically swinging the temperature of adsorbent beds, TSA processes can be used to separate gases in a mixture when used with an adsorbent that is selective for one or more of the components in a gas mixture.
Conventional swing adsorption vessels can contain a plurality of individual monolith adsorbent contactors within a cylindrical vessel. The monolith contactors can have multiple substantially parallel gas flow channels running along the longitudinal axis of the contactor, with an adsorbent material lining the walls of the open channels. Various engineering problems limit the flow through capacity of such adsorption vessels. These problems may be further complicated by the swing adsorption process. For example, TSA processes have to overcome substantial challenges in designing equipment to achieve these process needs. Some of the challenges include: (a) rapid cycling of pressure; (b) rapid cycling of temperatures; (c) high area density requirements; and/or (d) forming sufficient microchannels with sufficient adsorbent material. Accordingly, there remains a need in the art for monolith designs that mitigate at least the above-mentioned problems, especially those associated with undesirable gaseous steam paths between contactors.
U.S. Pat. No. 8,900,347 describes a temperature swing adsorption apparatus. The apparatus includes axial thermally conductive filaments that can assist with heating and/or cooling of the adsorbent.
U.S. Pat. No. 8,784,533 describes a temperature and/or pressure swing adsorption process using a solid adsorbent, such as an adsorbent provided as a parallel channel contactor. The temperature of the solid adsorbent can be controlled by introducing a heating and/or cooling fluid through heating and/or cooling channels in the adsorbent that are not in fluid communication with the channels that provide the feed gas for separation. This can allow physical contact between the heating and/or cooling fluid without exposing the gas being separated to the fluid.
U.S. Pat. No. 9,034,078 describes a parallel plate contactor for adsorption processes. The parallel plate contactor can include separate passages for a utility fluid and for a gas containing a gas component for adsorption.